Itchy and runny nose may be caused by cold, allergic rhinitis and vasomotor rhinitis. 1. Colds: Colds can cause nasal symptoms, manifested as itchy nose, nasal congestion, runny nose, sneezing and other symptoms. Colds are mostly caused by viral infections, which are self-limiting, but the duration of the disease will be longer when the resistance is low or when it is secondary to bacterial infections. 2. Allergic rhinitis: Most of the allergic rhinitis is caused by the sensitivity of one’s own body, and a series of allergic reactions, such as itchy nose, runny nose, sneezing, nasal congestion, etc., occur after contacting allergic substances (e.g., dust and pollen) or eating allergic foods (e.g., seafood, etc.). 3. Vasomotor rhinitis: It is often caused by autonomic nervous system dysfunction, which is characterized by itchy nose and sneezing after exercise, alternating hot and cold stimuli or diet. If there is no trend of self-healing in the short term, the patient should actively seek medical treatment, and standardize the diagnosis and treatment after examination by a specialist doctor.